Benchmarks: Add Feature - Add optimizer definition in Model Base (#13)

* add optimizer definition and function to create torch optimizer.

* move optimizer enum into model_base module.
Co-authored-by: Guoshuai Zhao <guzhao@microsoft.com>

superbench/benchmarks/model_benchmarks/model_base.py

@@ -11,6 +11,13 @@
 from superbench.benchmarks.context import Enum
 
 
+class Optimizer(Enum):
+    """The Enum class representing different optimizers."""
+    SGD = 'sgd'
+    ADAM = 'adam'
+    ADAMW = 'adamw'
+
+
 class DistributedImpl(Enum):
     """The Enum class representing different distributed implementations."""
     DDP = 'ddp'